1. Field of the Invention
The present invention relates to cabinets and, more particularly, to a cabinet with an environmentally-sealed air-to-air heat exchanger.
2. Description of the Related Art
Telecommunication circuits, such as line cards, are commonly housed in electronics cabinets that sit outside in residential and commercial neighborhoods. The cabinets are water tight and air tight to prevent water and dust from entering the cabinets and reducing the useful life of the line cards inside the cabinets.
One trend in the telecommunications industry is to make line cards that provide more than basic plain old telephone service (POTS), such as line cards that provide both basic POTS and XDSL broadband data service. Line cards which provide more than basic POTS, however, tend to consume more power and generate more heat than basic POTS cards.
Thus, as the power consumption of the line cards increases, more and more heat must be removed from inside the cabinets, where the equipment is housed and operates. Since the cabinets are air tight and water tight, heat removal must take place through a boundary surface by using, for example, an air-to-air heat exchanger.
FIG. 1 shows a perspective view that illustrates a prior-art electronics cabinet 100. As shown in FIG. 1, cabinet 100 includes a base plate 110, a top plate 112, and a number of side walls 114 that are connected to base plate 110 and top plate 112. In addition, cabinet 100 includes a rack 116 that holds telecommunication equipment, and a first door 118 that is connected to a side wall 114 via hinges or other rotational means to provide access to the interior of cabinet 100.
As further shown in FIG. 1, electronics cabinet 100 includes a second door 118A, and an air-to-air heat exchanger 120. Second door 118A, which has a large opening formed through door 118A, is also connected to a side wall 114 via hinges or other rotational means to further provide access to the interior of cabinet 100. Air-to-air heat exchanger 120, in turn, sits entirely within the opening of second door 118A.
However, one problem with a conventional door-mounted air-to-air heat exchanger, such as heat exchanger 120, is that water and dust can enter the external air flow path of the heat exchanger. As a result, when the heat exchanger or the installation of the heat exchanger is defective, such as when the sealant was improperly applied, the defect can allow water and dust to be introduced into the inside of the cabinet.
Thus, there is a need for an environmentally-sealed air-to-air heat exchanger that prevents the introduction of water and dust into the inside of the cabinet, even when the heat exchanger or the installation of the heat exchanger is defective.